Webcam issues with SKYPE / Yahoo Messenger

-Unable to use HP webcam video in skype (or) yahoo messenger-But the webcam works fine with Arcsoft web companion (S/w shipped with the webcam)

-OS installed on the computer is WINDOWS 7 64bit (but having similar issues on VISTA 32bit as well) -When tried to use with SKYPE (Or) Yahoo, it comesup with an error : "Cant start video renderer.Check you`ve got a valid directx installation" or the Video screen remains blank.-Also checked that latest DirectX are installed on the Computer-USB ports are working perfectly fine, as other USB devices are detected-Unplugged the webcam, while in use and also tried it on diff. USB ports-Did msconfig and disabled startup items which can use webcam-Checked with the services-Uninstalled and re-installed the webcam S/W ...still the same-Updated the Graphic card drivers and also uninstalled mirror drivers-Also tried with diff. resolutions..still the same-And there are no updates for the webcam-Again uninstalled and reinstalled the webcam in vista mode (using the setup file in MASTER INSTALLER FOLDER) ... but no go-Again uninstalled and reinstalled the webcam in xp + sp2 mode (using the setup file in MASTER INSTALLER FOLDER) ..but no go